I have downloaded and installed git for windows (msysgit) and frequently used the included git bash. Whenever I run vim from git bash my _vimrc file is not loaded because there is syntax highlighting or anything. When I run the same command to start vim form with in windows command line (cmd) instead of git bash it works as described in my _vimrc file. The only customization I have done to git bash is to add the following bash_profile to C:\Program Files (x86)\Git\etc